JP7049321B2 - A sensitizing dye, a sensitizing dye composition for photoelectric conversion, a photoelectric conversion element using the same, and a dye sensitized solar cell. - Google Patents

Description

The present invention relates to a photoelectric conversion sensitizing dye composition used for a sensitizing dye and a dye sensitizing type photoelectric conversion element, a photoelectric conversion element using the photoelectric conversion sensitizing dye composition, and a dye sensitized solar cell. ..

In recent years, carbon dioxide generated from fossil fuels such as coal, oil, and natural gas has caused global warming as a greenhouse gas and environmental destruction due to global warming. There is concern that global environmental destruction will continue to progress. Under these circumstances, the use of renewable energy, which is unlikely to be depleted unlike fossil fuels, is being energetically studied. The importance of using solar energy, mainly solar power generation, as a next-generation major renewable energy power generation method that can contribute to the prevention of global warming instead of thermal power generation and nuclear power generation that consume fossil fuels. It is becoming more and more popular, and it is being developed and applied in various fields, from power generation and charging of watches and portable small electronic devices to houses where utility costs can be saved, and small-scale power generation facilities in buildings and fallow lands. Is progressing.

As a means of photovoltaic power generation, a photoelectric conversion element that converts the energy of sunlight into electric energy is used in a solar cell, and the solar cell includes a single crystal, a polycrystal, an amorphous silicon-based material, gallium arsenic, and sulfide. Inorganic solar cells such as compound semiconductor-based solar cells such as cadmium and indium copper selenium have been mainly studied, and are now widely used in houses and small-scale power generation facilities. However, these inorganic solar cells have problems such as high manufacturing cost and difficulty in securing raw materials.

On the other hand, although the photoelectric conversion efficiency and durability are still much lower than those of inorganic solar cells, organic solar cells such as organic thin-film solar cells and dye-sensitized solar cells using various organic materials have also been developed. ing. Organic solar cells are said to be more advantageous than inorganic solar cells in terms of manufacturing cost, larger area, lighter weight, thinner film, translucency, wider absorption wavelength, flexibility, and securing of raw materials. ..

Among them, the dye-sensitized solar cell proposed by Gretzel et al. (See Non-Patent Document 1) is a thin film electrode made of titanium oxide porous as a semiconductor, and a ruthenium complex dye adsorbed on the semiconductor surface in order to widen the photosensitive wavelength range. It is a wet solar cell composed of an electrolytic solution containing iodine, and is expected to have a high photoelectric conversion efficiency comparable to that of an amorphous silicon solar cell. Dye-sensitized solar cells are attracting attention as next-generation solar cells because they have a simpler element structure than other solar cells and can be manufactured without large-scale manufacturing equipment.

Ruthenium complex is considered to be the most superior dye-sensitized dye used in dye-sensitized solar cells in terms of photoelectric conversion efficiency, but ruthenium is a precious metal and is disadvantageous in terms of manufacturing cost. When it is put into practical use and a large amount of ruthenium complex is required, resource constraints also become a problem. Therefore, research on dye-sensitized solar cells using organic dyes that do not contain precious metals such as ruthenium as sensitizing dyes is being actively conducted. As organic dyes containing no precious metal, coumarin-based pigments, cyanine-based pigments, merocyanine-based pigments, rodacyanine-based pigments, phthalocyanine-based pigments, porphyrin-based pigments, xanthene-based pigments and the like have been reported (for example, Patent Documents 1 to 3). reference).

Further, a compound having an indanone structure has also been proposed as an electron attracting unit for adsorbing to the surface of semiconductor particles such as titanium oxide and efficiently transporting excited electrons generated by the sensitizing dye to the semiconductor (for example). See Patent Documents 4-6). However, although these organic dyes have the advantages of being inexpensive, having a large absorption coefficient, and being able to control the absorption characteristics due to the variety of structures, they sufficiently satisfy the required characteristics in terms of photoelectric conversion efficiency and stability over time. The current situation is that we have not obtained anything that is satisfactory.

Japanese Unexamined Patent Publication No. 11-214730 Japanese Unexamined Patent Publication No. 11-238905 Japanese Unexamined Patent Publication No. 2011-26376 Japanese Unexamined Patent Publication No. 2011-207784 Japanese Unexamined Patent Publication No. 2012-51854 Japanese Unexamined Patent Publication No. 2016-6811

"Nature", (UK), 1991, Vol. 353, p. 737-740

The problem to be solved by the present invention is to provide a sensitizing dye having a novel structure capable of widening the photosensitive wavelength range, and further, a sensitizing dye composition for photoelectric conversion capable of efficiently extracting a current from the sensitizing dye. It is an object of the present invention to provide a photoelectric conversion element having good photoelectric conversion characteristics and a dye-sensitized solar cell.

In order to solve the above problems, the inventors have diligently studied the improvement of the photoelectric conversion characteristics of the sensitizing dye, and as a result, by using the sensitizing dye having a specific structure as the sensitizing dye for photoelectric conversion, the efficiency and durability are high. It has been found that a sex photoelectric conversion element can be obtained. That is, the present invention is composed of the following contents.

1. 1. A sensitizing dye represented by the following general formula (1).

[In the formula, Ar represents an aryl group having 6 to 36 carbon atoms which may have a substituent.
R ¹ to R ⁴ may be the same or different, and hydrogen atom, halogen atom, cyano group, hydroxyl group, nitro group, nitroso group, thiol group,
A linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent,
A cycloalkyl group having 3 to 36 carbon atoms which may have a substituent,
A linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent,
A cycloalkoxy group having 3 to 36 carbon atoms which may have a substituent,
A linear or branched alkenyl group having 2 to 36 carbon atoms which may have a substituent,
Aryl groups having 6 to 36 carbon atoms, which may have substituents,
Alternatively, it represents an amino group having 0 to 36 carbon atoms which may have a substituent.
R ¹ to R ⁴ may be bonded to each other by adjacent groups to form a ring.
X represents a sulfur atom, an oxygen atom or CR ⁵ R ⁶ . R ⁵ and R ⁶ may be the same or different, and may have a substituent. They may have a linear or branched alkyl group having 1 to 36 carbon atoms, or a substituent. Represents an aryl group having 6 to 36 carbon atoms.
Z represents a monovalent group. ]

2. 2. In the general formula (1), a sensitizing dye in which Z is a monovalent group represented by the following general formula (2).

[In the formula, R ⁷ to R ¹² may be the same or different, hydrogen atom,
A linear or branched alkyl group having 1 to 18 carbon atoms which may have a substituent,
A linear or branched alkoxy group having 1 to 18 carbon atoms which may have a substituent,
Alternatively, it represents a linear or branched alkenyl group having 2 to 18 carbon atoms which may have a substituent.
R ⁷ and R ⁸ , R ⁹ and R ¹⁰ , and R ¹¹ and R ¹² may be connected to each other to form a ring.
m represents an integer of 0 to 2, n represents an integer of 0 to 4, and when m is 2 or n is an integer of 2 to 4, a plurality of R ⁷ to R ¹² existing are R ⁷ to each other. , R ^8s , R ^9s , R ^10s , R ^11s , and R ^12s may be the same or different from each other.
It is assumed that R ¹³ and R ¹⁴ represent a hydrogen atom or an acidic group, and at least one of R ¹³ or R ¹⁴ is an acidic group. ]

3. 3. The sensitizing dye according to 2 above, wherein in the general formula (2), R ⁷ to R ¹² are hydrogen atoms or unsubstituted linear or branched alkyl groups having 1 to 6 carbon atoms.

4. The sensitizing dye according to 2 or 3 above, wherein m is 0 and n is 0 in the general formula (2).

5. A sensitizing dye composition for photoelectric conversion containing the sensitizing dye.

6. A photoelectric conversion element using the sensitizing dye composition for photoelectric conversion.

7. A dye-sensitized solar cell using the photoelectric conversion element.

According to the sensitizing dye according to the present invention, it is possible to obtain a sensitizing dye composition for photoelectric conversion capable of efficiently extracting an electric current. Further, by using the photoelectric conversion sensitizing dye composition, a highly efficient and highly durable photoelectric conversion element and a dye sensitized solar cell can be obtained.

It is schematic cross-sectional view which shows the structure of the photoelectric conversion element of the Example of this invention and the comparative example.

Hereinafter, embodiments of the present invention will be described in detail. The photoelectric conversion sensitizing dye composition comprising the sensitizing dye of the present invention is used as a sensitizer in a dye sensitizing type photoelectric conversion element. In the specification of the present application, the "sensitizing dye" refers to a compound represented by the general formula (1), and the "photoelectric conversion sensitizing dye composition" refers to a compound represented by the general formula (1). A composition containing one or more of the above, and optionally other sensitizing dyes not belonging to the present invention. In the photoelectric conversion element of the present invention, a light electrode formed by adsorbing a dye on a semiconductor layer on a conductive support and a counter electrode are typically arranged to face each other via an electrolyte layer.

Hereinafter, the sensitizing dye represented by the general formula (1) will be specifically described, but the present invention is not limited thereto.

In the general formula (1), "an aryl group having 6 to 36 carbon atoms" in "an aryl group having 6 to 36 carbon atoms which may have a substituent" represented by Ar or R ¹ to R ⁶ . Specific examples thereof include aryl groups such as a phenyl group, a naphthyl group, a biphenyl group, an anthryl group, a phenanthryl group, a pyrenyl group, a triphenylenyl group, an indenyl group and a fluorenyl group. Here, the "aryl group" in the present invention represents an aromatic hydrocarbon group and a condensed polycyclic aromatic group, and among these, a phenyl group or a naphthyl group is preferable, and a phenyl group is more preferable.

Specific examples of the "halogen atom" represented by R ¹ to R ⁴ in the general formula (1) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In the general formula (1), the "linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent" represented by R ¹ to R ⁶ has "1 carbon atom number". Specific examples of the "36 linear or branched alkyl group" include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Linear alkyl groups; branched alkyl groups such as isopropyl group, isobutyl group, s-butyl group, t-butyl group and isooctyl group can be mentioned.

In the general formula (1), the "cycloalkyl group having 3 to 36 carbon atoms" in the "cycloalkyl group having 3 to 36 carbon atoms which may have a substituent" represented by ^R1 to ^R4 . Specific examples thereof include cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group and cyclodecyl group.

In the general formula (1), the "linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent" represented by R ¹ to R ⁴ has "1 carbon atom number". Specific examples of the "36 linear or branched alkoxy groups" include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group and nonyloxy group. Linear alkoxy groups such as decyloxy group; branched alkoxy groups such as isopropoxy group, isobutoxy group, s-butoxy group, t-butoxy group and isooctyloxy group can be mentioned.

In the general formula (1), the "cycloalkoxy group having 3 to 36 carbon atoms" in the "cycloalkoxy group having 3 to 36 carbon atoms which may have a substituent" represented by ^R1 to ^R4 . Specific examples thereof include cycloalkoxy groups such as cyclopropoxy group, cyclobutoxy group, cyclopentyloxy group and cyclohexyloxy group.

In the general formula (1), the "linear or branched alkenyl group having 2 to 36 carbon atoms which may have a substituent" represented by R ¹ to R ⁴ has "2 carbon atoms". Specific examples of the "36 linear or branched alkenyl groups" include alkenyl groups such as vinyl group, allyl group, isopropenyl group, 2-butenyl group and 1-hexenyl group, or alkenyl groups thereof. Examples thereof include a plurality of bonded linear or branched alkenyl groups.

In the general formula (1), the "amino group having 0 to 36 carbon atoms which may have a substituent" represented by R ¹ to R ⁴ is specifically an unsubstituted amino group; a methyl amino. Examples thereof include amino groups having a substituent having 0 to 36 carbon atoms, such as a group, a dimethylamino group, a diethylamino group, an ethylmethylamino group, a methylpropylamino group, a di-t-butylamino group and a diphenylamino group.

In the general formula (1), the "substituted group" in "Ar or an aryl group having 6 to 36 carbon atoms having a substituent" represented by R ¹ to R ⁶ or
"Cycloalkyl group having a substituent and having 3 to 36 carbon atoms" represented by R ¹ to R ⁴ ,
"Linear or branched alkoxy group having 1 to 36 carbon atoms having a substituent",
The "substituent" in the "cycloalkoxy group having 3 to 36 carbon atoms having a substituent" or the "amino group having 0 to 36 carbon atoms having a substituent"
Specifically, halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom;
Cyano group; hydroxyl group; nitro group; nitroso group; thiol group;
A linear alkyl group having 1 to 30 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group and a decyl group;
A branched alkyl group having 3 to 30 carbon atoms such as an isopropyl group, an isobutyl group, an s-butyl group, a t-butyl group, and an isooctyl group;
A cycloalkyl group having 3 to 30 carbon atoms such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group;
A linear alkoxy group having 1 to 30 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, and a decyloxy group;
A branched alkoxy group having 3 to 30 carbon atoms such as an isopropoxy group, an isobutoxy group, an s-butoxy group, a t-butoxy group, and an isooctyloxy group;
Cycloalkoxy groups having 3 to 30 carbon atoms such as cyclopropoxy group, cyclobutoxy group, cyclopentyloxy group, cyclohexyloxy group;
A vinyl group, an allyl group, an isopropenyl group, a 2-butenyl group, a 1-hexenyl group, or a linear or branched alkenyl group having 2 to 30 carbon atoms to which a plurality of these alkenyl groups are bonded;
Aryl groups having 6 to 30 carbon atoms such as phenyl group, naphthyl group, biphenyl group, anthryl group, phenanthryl group, pyrenyl group, triphenylenyl group, indenyl group and fluorenyl group;
Unsubstituted amino group; Substituents having 1 to 30 carbon atoms such as methylamino group, dimethylamino group, diethylamino group, ethylmethylamino group, methylpropylamino group, dit-butylamino group and diphenylamino group. Amino group having;
Carboxyl groups; carboxylic acid ester groups such as methyl ester groups and ethyl ester groups; and the like can be mentioned. Only one of these "substituents" may be contained, a plurality of these "substituents" may be contained, and when a plurality of these "substituents" are contained, they may be the same or different from each other. Further, these "substituents" may further have the above-exemplified substituents.

In the general formula (1), "a linear or branched alkyl group having a substituent and having 1 to 36 carbon atoms" represented by R ¹ to R ⁶ or
The "substituent" in the "linear or branched alkenyl group having 2 to 36 carbon atoms having a substituent" represented by R ¹ to R ⁴ is
Specifically, halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom;
Cyano group; hydroxyl group; nitro group; nitroso group; thiol group;
Cycloalkyl groups having 3 to 34 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group;
A linear alkoxy group having 1 to 34 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, and a decyloxy group;
A branched alkoxy group having 3 to 34 carbon atoms such as an isopropoxy group, an isobutoxy group, an s-butoxy group, a t-butoxy group, and an isooctyloxy group;
Cycloalkoxy groups having 3 to 34 carbon atoms such as cyclopropoxy group, cyclobutoxy group, cyclopentyloxy group, cyclohexyloxy group;
Aryl groups having 6 to 34 carbon atoms such as phenyl group, naphthyl group, biphenyl group, anthryl group, phenanthryl group, pyrenyl group, triphenylenyl group, indenyl group and fluorenyl group;
Unsubstituted amino group; Substituents having 1 to 34 carbon atoms such as methylamino group, dimethylamino group, diethylamino group, ethylmethylamino group, methylpropylamino group, dit-butylamino group and diphenylamino group. Amino group having;
Carboxyl groups; carboxylic acid ester groups such as methyl ester groups and ethyl ester groups; and the like can be mentioned. Only one of these "substituents" may be contained, a plurality of these "substituents" may be contained, and when a plurality of these "substituents" are contained, they may be the same or different from each other. Further, these "substituents" may further have the above-exemplified substituents.

In the general formula (1), R ¹ to R ⁴ have a hydrogen atom, a halogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms which may have a substituent, and a substituent. An aryl group having 6 to 24 carbon atoms which may be used, or an amino group having 0 to 24 carbon atoms which may have a substituent is preferable, and a hydrogen atom or a carbon which may have a substituent may be used. An aryl group having 6 to 24 atoms is more preferable.

In the general formula (1), R ¹ to R ⁴ represent substituents as described above, but adjacent groups may be bonded to each other to form a ring, and these rings are single-bonded. Alternatively, they may be bonded to each other to form a ring by a bond via any atom of a nitrogen atom, an oxygen atom or a sulfur atom. These rings are preferably benzene rings.

In the general formula (1), when X is CR ⁵ R ⁶ , R ⁵ and R ⁶ are linear or branched alkyl groups having 1 to 24 carbon atoms which may have a substituent. Alternatively, an aryl group having 6 to 24 carbon atoms which may have a substituent is preferable, and a linear or branched alkyl group having 1 to 12 carbon atoms which may have a substituent is more preferable. preferable.

In the general formula (1), Z represents a monovalent group, and is preferably a monovalent group represented by the general formula (2).

In the general formula (2), the "linear or branched alkyl group having 1 to 18 carbon atoms which may have a substituent" represented by R ⁷ to R ¹² has "1 carbon atom number". Specific examples of the "to 18 linear or branched alkyl groups" include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group and the like. Linear alkyl groups; branched alkyl groups such as isopropyl group, isobutyl group, s-butyl group, t-butyl group and isooctyl group can be mentioned.

In the general formula (2), the "linear or branched alkoxy group having 1 to 18 carbon atoms which may have a substituent" represented by R ⁷ to R ¹² has "1 carbon atom number". Specific examples of the "to 18 linear or branched alkoxy groups" include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group and nonyloxy group. Linear alkoxy groups such as decyloxy group; branched alkoxy groups such as isopropoxy group, isobutoxy group, s-butoxy group, t-butoxy group and isooctyloxy group can be mentioned.

In the general formula (2), the "linear or branched alkenyl group having 2 to 36 carbon atoms which may have a substituent" represented by R ⁷ to R ¹² has "2 carbon atoms". Specific examples of the "to 18 linear or branched alkenyl groups" include alkenyl groups such as vinyl group, allyl group, isopropenyl group, 2-butenyl group and 1-hexenyl group, or alkenyl groups thereof. Examples thereof include a linear or branched alkenyl group having a plurality of bonds.

In the general formula (2), "a linear or branched alkyl group having a substituent and having 1 to 18 carbon atoms" represented by R ⁷ to R ¹² .
"Substituent" in "a linear or branched alkoxy group having 1 to 18 carbon atoms having a substituent" or "a linear or branched alkenyl group having 2 to 18 carbon atoms having a substituent". as,
Specifically, halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom;
Cyano group; hydroxyl group; nitro group; nitroso group; thiol group;
Cycloalkyl groups having 3 to 16 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group;
A linear alkoxy group having 1 to 16 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, and a decyloxy group;
A branched alkoxy group having 3 to 16 carbon atoms such as an isopropoxy group, an isobutoxy group, an s-butoxy group, a t-butoxy group, and an isooctyloxy group;
Cycloalkoxy groups having 3 to 16 carbon atoms such as cyclopropoxy group, cyclobutoxy group, cyclopentyloxy group, cyclohexyloxy group;
Aryl groups having 6 to 34 carbon atoms such as phenyl group, naphthyl group, biphenyl group, anthryl group, phenanthryl group, pyrenyl group, triphenylenyl group, indenyl group and fluorenyl group;
Unsubstituted amino group; Substituents having 1 to 16 carbon atoms such as methylamino group, dimethylamino group, diethylamino group, ethylmethylamino group, methylpropylamino group, dit-butylamino group and diphenylamino group. Amino group having;
Carboxyl groups; carboxylic acid ester groups such as methyl ester groups and ethyl ester groups; and the like can be mentioned. Only one of these "substituents" may be contained, a plurality of these "substituents" may be contained, and when a plurality of these "substituents" are contained, they may be the same or different from each other. Further, these "substituents" may further have the above-exemplified substituents.

In the general formula (2), R ⁷ to R ¹² are preferably a linear or branched alkyl group having 1 to 18 carbon atoms which may have a hydrogen atom or a substituent, and more preferably a hydrogen atom. ..

In the general formula (2), R ⁷ to R ¹² represent substituents as described above, but adjacent groups may be bonded to each other to form a ring, and these rings are single-bonded. Alternatively, they may be bonded to each other to form a ring by a bond via any atom of a nitrogen atom, an oxygen atom or a sulfur atom.

In the general formula (2), m and n represent the number of aryl groups and thiophene groups having the role of a linking group that carries the electrons excited in the dye moiety to the indanone group which is an electron attraction part, respectively. m represents an integer of 0 to 2, preferably 0 or 1, and n is preferably 0 to 2, more preferably 0 or 1.

In the general formula (2), R ¹³ and R ¹⁴ represent a hydrogen atom or an acidic group, but at least one of R ¹³ or R ¹⁴ is assumed to be an acidic group. Specific examples of the acidic group represented by R ¹³ and R ¹⁴ include a carboxyl group, a sulfonic acid group, a phosphoric acid group, a hydroxamic acid group, a phosphonic acid group, a boric acid group, a phosphinic acid group, and a silanol group. Can be done. Among these acidic groups, a carboxyl group or a phosphonic acid group is preferable, and a carboxyl group is more preferable, because the sensitizing dye can be easily adsorbed on the surface of the semiconductor layer and the photoelectric conversion characteristics are improved.

In the present invention, the sensitizing dye represented by the general formula (1) includes all possible stereoisomers. Any stereoisomer can be suitably used as the sensitizing dye in the present invention. For example, in the general formula (1), when Z is a monovalent group represented by the general formula (2), R ¹³ is a hydrogen atom, and R ¹⁴ is a carboxyl group, the sensitizing dye of the present invention is used. , The compounds represented by the following general formulas (3) and (4) are included. Further, it may be a mixture of two or more kinds selected from these stereoisomers.

Specific examples of the compound of the sensitizing dye of the present invention represented by the general formula (1) are shown in the following formulas, but the present invention is not limited thereto. For example, X in the sensitizing dye represented by the general formula (1) represents a sulfur atom, an oxygen atom or CR ⁵ CR ⁶ , but only a compound having any of them in the X portion of the following exemplified compound. Although shown, the exemplary compound may be another compound having X. In addition, the following exemplary compounds show an example of possible steric isomers and include all other steric isomers. Further, it may be a mixture of two or more kinds of stereoisomers.

The sensitizing dye of the present invention represented by the general formula (1) can be synthesized by a known method. The following is a synthesis example in which Z is a monovalent group represented by the general formula (2) in the general formula (1). In the general formula (2), except for the case where m is 0 and n is 0 (m = n = 0), the bromo form represented by the following general formula (5) and having a corresponding substituent and the following general The following general formula (8) is represented by the following general formula (6) or the following general formula (7) by performing a cross-coupling reaction such as Suzuki coupling with a boronic acid having a corresponding substituent and a formyl group, respectively. The formyl form represented by can be synthesized.

In the synthesis example of the formyl compound represented by the general formula (8), when m is 1 or 2 and n is 0, the boronic acid having a formyl group represented by the general formula (6) is 4 -Formylphenylboronic acid and 4- (4-formylphenyl) phenylboronic acid can be mentioned. Further, in the above synthesis example, when m is 0 and n is 1 to 4, the boronic acid having a formyl group represented by the general formula (7) is 5-formyl-2-thiopheneboronic acid or 5 '-Formyl-2,2'-bithiophene-5-boronic acid and the like can be mentioned. Further, when m is 1 or 2 and n is 1 to 4, a boronic acid having a bromo form represented by the general formula (5) and a formyl group represented by the same general formula (7) described above. By carrying out the same cross-coupling reaction as in the above synthesis example, the formyl compound represented by the general formula (8) can be synthesized.

In the synthesis example of the formyl form represented by the general formula (8), when m is 0 and n is 0 (m = n = 0), the bromo form represented by the general formula (5) and the bromo form are used. By capturing aryllithium obtained by metal halogen exchange with butyllithium or the like with N, N-dimethylformamide (DMF), a formyl compound (m = n = 0) represented by the general formula (8) can be obtained. Can be synthesized.

Subsequently, the sensitization of the present invention is carried out by performing a condensation reaction between the formyl compound represented by the general formula (8) obtained as described above and the indenone compound represented by the following general formula (9). Dyes can be synthesized. However, Ar and R ¹ to R ¹⁴ in the general formulas (5) to (9) in the above synthesis example are the same as Ar and R ¹ to R ¹⁴ in the general formulas (1) and the general formula (2) in the present invention. Represents meaning. Therefore, in the general formulas (5) to (9), R ⁷ to R ¹² having a plurality of m or n are R ⁷ to each other, R ⁸ to each other, R ⁹ to each other, R ¹⁰ to each other, and R ¹¹ to each other. They may be the same or different from each other, and R ¹³ and R ¹⁴ may represent hydrogen atoms or acidic groups, and at least one of R ¹³ or R ^{14 shall} be an acidic group.

As the starting material of the above formula (5) or the like, a commercially available product may be used, or a product synthesized by a known method may be used. The indenone compound represented by the general formula (9) can be easily synthesized by the method described in Patent Documents 4 to 6 described above.

As a method for purifying the sensitizing dye compound of the present invention represented by the general formula (1), purification by column chromatography; adsorption purification with silica gel, activated charcoal, activated clay, etc.; recrystallization with a solvent, crystallization method, etc. Known methods can be mentioned. In addition, these compounds can be identified by nuclear magnetic resonance spectroscopy (NMR) or the like.

The sensitizing dye of the present invention may be used alone or in combination of two or more. In addition, the sensitizing dye of the present invention can be used in combination with other sensitizing dyes that do not belong to the present invention. Specific examples of other sensitizing dyes include the above general formula (1) such as ruthenium complex, coumarin dye, cyanine dye, merocyanine dye, rodacyanine dye, phthalocyanine dye, porphyrin dye, and xanthene dye. Examples include sensitizing dyes other than the represented sensitizing dyes. When the sensitizing dye of the present invention is used in combination with these other sensitizing dyes as a sensitizing dye composition for photoelectric conversion, the amount of the other sensitizing dye used for the sensitizing dye of the present invention is 10 to 200. The weight is preferably%, and more preferably 20 to 100% by weight.

The sensitizing dye of the present invention can be applied as a spectral sensitizing dye for various imaging materials such as silver halide, zinc oxide, and titanium oxide, a photocatalyst, and a photofunctional material, and is a dye-sensitized photoelectric conversion. It can also be applied as a sensitizing dye composition for photoelectric conversion used for elements and the like. In the present invention, the method for producing a dye-sensitized photoelectric conversion element is not particularly limited, but a semiconductor layer is formed on a conductive support (electrode), and the semiconductor layer is formed with the sensitizing dye composition for photoelectric conversion of the present invention. A method of manufacturing an optical electrode by adsorbing (supporting) an object is preferable (see FIG. 1. Needless to say, the figure is not a faithful scale of an actual element because it gives priority to contributing to understanding). As a method for adsorbing the dye, a method of immersing the semiconductor layer in a solution obtained by dissolving the dye in a solvent for a long time is common. When two or more kinds of the sensitizing dye of the present invention are used in combination, or when the sensitizing dye of the present invention is used in combination with another sensitizing dye, a mixed solution of all the dyes to be used is prepared and the semiconductor layer is immersed. Alternatively, a separate solution may be prepared for each dye, and the semiconductor layer may be immersed in each solution in order.

In the present invention, in addition to the metal plate, a glass substrate or a plastic substrate having a conductive layer having a conductive material on the surface can be used as the conductive support. Specific examples of the conductive material include metals such as gold, silver, copper, aluminum and platinum, conductive transparent oxide semiconductors such as fluorine-doped tin oxide and indium-tin composite oxide, and carbon. However, it is preferable to use a glass substrate coated with a fluorine-doped tin oxide thin film.

Specific examples of the semiconductor forming the semiconductor layer in the present invention include metals such as titanium oxide, zinc oxide, tin oxide, indium oxide, zirconium oxide, tungsten oxide, tantalum oxide, iron oxide, gallium oxide, nickel oxide, and yttrium oxide. Oxides; metal sulfides such as titanium sulfide, zinc sulfide, zirconium sulfide, copper sulfide, tin sulfide, indium sulfide, tungsten sulfide, cadmium sulfide, silver sulfide; titanium selenium, zirconium selenium, indium selenium, tungsten selenium Metallic sulphides such as; single semiconductors such as silicon and germanium can be mentioned. These semiconductors can be used not only alone but also in combination of two or more. In the present invention, it is preferable to use one or more selected from titanium oxide, zinc oxide, and tin oxide as the semiconductor.

The aspect of the semiconductor layer in the present invention is not particularly limited, but a thin film having a porous structure composed of fine particles is preferable. When the substantially surface area of the semiconductor layer is increased due to the porous structure or the like and the amount of dye adsorbed on the semiconductor layer is increased, a highly efficient photoelectric conversion element can be obtained. The semiconductor particle size is preferably 5 to 500 nm, more preferably 10 to 100 nm. The film thickness of the semiconductor layer is usually 2 to 100 μm, but more preferably 5 to 20 μm. As a method for producing a semiconductor layer, a paste containing semiconductor fine particles is applied onto a conductive substrate by a wet coating method such as a spin coating method, a doctor blade method, a squeegee method, or a screen printing method, and then a solvent or an additive is added by firing. Examples thereof include a method of forming a film by removing the film, a method of forming a film by a sputtering method, a vapor deposition method, an electrodeposition method, an electrodeposition method, a microwave irradiation method, and the like, but the method is not limited thereto.

In the present invention, as the paste containing the semiconductor fine particles, a commercially available product may be used, or a paste prepared by dispersing the commercially available semiconductor fine powder in a solvent may be used. Specific examples of the solvent used when preparing the paste include water; alcohol solvents such as methanol, ethanol and isopropyl alcohol; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; n-hexane, cyclohexane and benzene. A hydrocarbon solvent such as toluene can be mentioned, but the present invention is not limited thereto. In addition, these solvents can be used alone or as a mixed solvent of two or more kinds.

In the present invention, as a method for dispersing the semiconductor fine powder in a solvent, the powder may be ground in a mortar or the like, and then a disperser such as a ball mill, a paint conditioner, a vertical bead mill, a horizontal bead mill, or an attritor is used. You may. When preparing the paste, it is preferable to add a surfactant or the like in order to prevent aggregation of the semiconductor fine particles, and it is preferable to add a thickener such as polyethylene glycol in order to thicken the paste.

The adsorption of the sensitizing dye composition for photoelectric conversion of the present invention on the surface of the semiconductor layer is performed, for example, by immersing the semiconductor layer in the dye solution for 30 minutes to 100 hours at room temperature or 10 minutes to 24 hours under heating conditions. It can be done by leaving it alone. In that case, it is preferably left at room temperature for 10 to 20 hours, and the dye concentration in the dye solution is preferably 10 to 2000 μM, more preferably 50 to 500 μM.

Specific examples of the solvent used for adsorbing the photoelectric conversion sensitizing dye composition of the present invention on the surface of the semiconductor layer include alcohol solvents such as methanol, ethanol, isopropyl alcohol and t-butyl alcohol; acetone, Ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl formate, ethyl acetate and n-butyl acetate; ether solvents such as diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran and 1,3-dioxolane; Amido solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone; nitrile solvents such as acetonitrile, methoxynitrile, propionitrile; dichloromethane, chloroform, bromoform, o-di Halogenated hydrocarbon solvents such as chlorobenzene; examples include, but are not limited to, hydrocarbon solvents such as n-hexane, cyclohexane, benzene, and toluene. These solvents are used alone or as a mixed solvent of two or more kinds. Among these solvents, it is preferable to use one or more selected from methanol, ethanol, t-butyl alcohol, acetone, methyl ethyl ketone, tetrahydrofuran, and acetonitrile.

When the sensitizing dye composition for photoelectric conversion of the present invention is adsorbed on the surface of the semiconductor layer, a cholic acid or a cholic acid derivative such as deoxycholic acid, chenodeoxycholic acid, lithocolic acid, or dehydrocholic acid is dissolved in the dye solution. However, it may be co-adsorbed with the dye. By using cholic acid or a cholic acid derivative, association between dyes is suppressed, and electrons can be efficiently injected from the dye to the semiconductor layer in the photoelectric conversion element. When cholic acid or a cholic acid derivative is used, their concentration in the dye solution is preferably 0.1 to 100 mM, more preferably 0.5 to 10 mM.

The counter electrode (electrode) used in the photoelectric conversion element of the present invention is not particularly limited as long as it has conductivity, but a conductive material having catalytic ability is used in order to promote the redox reaction of redox ions. It is preferable to do so. Specific examples of the conductive material include, but are not limited to, platinum, rhodium, ruthenium, carbon and the like. In the present invention, it is particularly preferable to use a platinum thin film formed on a conductive support as a counter electrode. As a method for producing a conductive thin film, a paste containing a conductive material is applied onto a conductive substrate by a wet coating method such as a spin coating method, a doctor blade method, a squeegee method, or a screen printing method, and then a solvent is obtained by firing. Examples thereof include a method of forming a film by removing additives and a method of forming a film by a sputtering method, a vapor deposition method, an electrodeposition method, an electrodeposition method, a microwave irradiation method, and the like, but the present invention is not limited thereto.

In the photoelectric conversion element of the present invention, an electrolyte is filled between a pair of facing electrodes to form an electrolyte layer. As the electrolyte to be used, a redox electrolyte is preferable. Examples of the redox electrolyte include, but are not limited to, redox ion pairs such as iodine, bromine, tin, iron, chromium, and anthraquinone. Of these, iodine-based electrolytes and bromine-based electrolytes are preferable. In the case of an iodine-based electrolyte, for example, a mixture of potassium iodide, lithium iodide, dimethylpropylimidazolium iodide and iodine is used. In the present invention, it is preferable to use an electrolytic solution obtained by dissolving these electrolytes in a solvent. The concentration of the electrolyte in the electrolytic solution is preferably 0.05 to 5 M, more preferably 0.2 to 1 M.

Examples of the solvent for dissolving the electrolyte include nitrile solvents such as acetonitrile, methoxyacetonitrile, propionitrile, 3-methoxypropionitrile and benzonitrile; ether solvents such as diethyl ether, 1,2-dimethoxyethane and tetrahydrofuran; N. , N-dimethylformamide, N, N-dimethylacetoamide and other amide solvents; ethylene carbonate, propylene carbonate and other carbonate solvents; γ-butyrolactone, γ-valerolactone and other lactone solvents, and the like. Not limited. These solvents are used alone or as a mixed solvent of two or more kinds. Among these solvents, a nitrile solvent is preferable.

In the present invention, the amine compound may be contained in the electrolytic solution in order to further improve the open circuit voltage and the fill factor of the dye-sensitized photoelectric conversion element. Examples of the amine compound include 4-t-butylpyridine, 4-methylpyridine, 2-vinylpyridine, N, N-dimethyl-4-aminopyridine, N, N-dimethylaniline, N-methylbenzimidazole and the like. .. The concentration of the amine compound in the electrolytic solution is preferably 0.05 to 5 M, more preferably 0.2 to 1 M.

As the electrolyte in the photoelectric conversion element of the present invention, a solid electrolyte using a polymer such as a gel-like electrolyte obtained by adding a gelling agent or a polymer or a polyethylene oxide derivative may be used. By using a gel-like electrolyte or a solid electrolyte, the volatilization of the electrolytic solution can be reduced.

In the photoelectric conversion element of the present invention, a solid charge transport layer may be formed between the pair of opposing electrodes instead of the electrolyte. The charge transport material contained in the solid charge transport layer is preferably a hole transport material. Specific examples of the charge transporting substance include inorganic hole transporting substances such as copper iodide, copper bromide, and copper thiocyanide, polypyrrole, polythiophene, poly-p-phenylene vinylene, polyvinylcarbazole, polyaniline, oxadiazole derivatives, and birds. Examples thereof include, but are not limited to, organic hole transporting substances such as phenylamine derivatives, pyrazoline derivatives, fluorenone derivatives, hydrazone compounds, and stylben compounds.

When the solid charge transport layer is formed by using the organic hole transport substance in the present invention, a film-forming binder resin may be used in combination. Specific examples of the film-forming binder resin include polystyrene resin, polyvinyl acetal resin, polycarbonate resin, polysulfone resin, polyester resin, polyphenylene oxide resin, polyallylate resin, alkyd resin, acrylic resin, and phenoxy resin. , Not limited to these. These resins can be used alone or as a copolymer of one or a mixture of two or more. The amount of these binder resins used for the organic hole transporting substance is preferably 20 to 1000% by weight, more preferably 50 to 500% by weight.

In the photoelectric conversion element of the present invention, the electrode (optical electrode) provided with the semiconductor layer on which the photoelectric conversion sensitizing dye composition is adsorbed serves as a cathode, and the counter electrode serves as an anode. Light such as sunlight may be emitted from either the light electrode side or the counter electrode side, but it is preferable to irradiate from the light electrode side. When irradiated with sunlight or the like, the dye absorbs the light and becomes an excited state to emit electrons. These electrons flow to the outside via the semiconductor layer and move to the opposite pole. On the other hand, the dye that has been oxidized by emitting electrons returns to the ground state by receiving the electrons supplied from the counter electrode via the ions in the electrolyte. This cycle causes a current to flow and functions as a photoelectric conversion element.

When evaluating the performance (characteristics) of the photoelectric conversion element of the present invention, the short-circuit current, open circuit voltage, fill factor, and photoelectric conversion efficiency are measured. The short-circuit current represents the current per 1 cm ² flowing between the two terminals when the output terminal is short-circuited, and the open circuit voltage represents the voltage between the two terminals when the output terminal is opened. The fill factor is a value obtained by dividing the maximum output (product of current and voltage) by the product of short-circuit current and open circuit voltage, and is mainly affected by internal resistance. The photoelectric conversion efficiency is obtained as a value obtained by dividing the maximum output (W) by the light intensity (W) per 1 cm ² and multiplying it by 100 to display it as a percentage.

The photoelectric conversion element of the present invention can be applied to a dye-sensitized solar cell, various optical sensors, and the like. In the dye-sensitized solar cell of the present invention, a photoelectric conversion element containing a photoelectric conversion sensitizing dye composition containing a sensitizing dye represented by the general formula (1) becomes a cell, and the required number of cells are arranged. It is obtained by modularizing it and providing a predetermined electrical wiring.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples. In the synthesis example, the compound was identified by ¹ H-NMR analysis (Nuclear magnetic resonance apparatus manufactured by JEOL Ltd., JNM-ECA-600).

[Synthesis Example 1] Synthesis of sensitizing dye (A-4) 1.20 g of a bromo solution represented by the following formula (10) and 16 mL of dehydrated tetrahydrofuran were placed in a nitrogen-substituted reaction vessel and stirred at −72 ° C. However, 1.5 mL of a 1.6 M n-butyllithium hexane solution was added dropwise, and the reaction was carried out for 1 hour. After the reaction, 0.3 mL of dehydrated dimethylformaldehyde was added dropwise to the reaction solution, and the reaction was carried out for 2 hours. The reaction solution was emptied into 50 mL of ice water, and the organic layer was extracted with methylene chloride. The organic layer was washed with water, separated, dried over magnesium sulfate, and concentrated under reduced pressure to obtain a crude product. The crude product is purified by column chromatography (carrier: silica gel, eluent: hexane / toluene = 9/1 (volume ratio)), and a yellow solid (0.78 g) of a formyl compound represented by the following formula (11) is obtained. Got

In a nitrogen-substituted reaction vessel, 0.300 g of the formyl compound represented by the above formula (11), 0.179 g of the indenone compound represented by the following formula (12), and acetic acid / toluene = 5/2 (volume ratio) are mixed. 13.5 mL of the liquid was added, and the mixture was stirred at 90 ° C. for 3 hours. After allowing the reaction solution to cool to 25 ° C., 50 mL of water was added and the mixture was stirred to extract the organic layer. The organic layer was washed successively with water and saturated brine, and dried to give the desired sensitizing dye as a deep purple solid (0.294 g, 75% yield).

The obtained dark purple solid was subjected to NMR analysis, and the following 26 hydrogen signals were detected and identified as a structure represented by the following formula (A-4) (carboxyl group hydrogen was not observed). ..

^{1 1} H-NMR (600 MHz, CDCl ₃ ): δ (ppm) = 6.01-6.05 (2H), 6.90-6.95 (2H), 7.05-7.08 (1H), 7 .23-7.27 (5H), 7.30-7.40 (8H), 7.42-7.50 (2H), 7.55-7.65 (1H), 7.94-8.01 (2H), 8.28-8.32 (1H), 8.36-8.40 (1H), 8.50-8.55 (1H).

[Synthesis Example 2] Synthesis of sensitizing dye (A-10) In a nitrogen-substituted reaction vessel, 1.50 g of a bromo compound represented by the above formula (10), 30 mL of toluene, 8 mL of ethanol, 8 mL of water, 5'- 0.81 g of formyl-2,2'-bithiophene-5-boronic acid and 0.62 g of potassium carbonate were added and stirred for 5 hours. After stirring, depressurization, degassing and nitrogen substitution in the reaction vessel were repeated 3 times. Next, 0.18 g of tetrakis (triphenylphosphine) palladium was added, and the mixture was stirred at 80 ° C. for 5 hours. After allowing the reaction solution to cool to 25 ° C., 10 mL of ethyl acetate and 30 mL of water were added and stirred to extract the organic layer. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure to obtain a crude product. The crude product is purified by column chromatography (carrier: silica gel, eluent: chloroform / hexane = 3/1 (volume ratio)), dried, and is a yellowish brown solid of a formyl compound represented by the following formula (13). 1.20 g) was obtained.

In a nitrogen-substituted reaction vessel, 0.64 g of the formyl compound represented by the above formula (13), 13.5 mL of a mixed solution of acetic acid / toluene = 5/2 (volume ratio), and indenone represented by the above formula (12). 0.29 g of the compound was added, and the mixture was stirred at 90 ° C. for 3 hours. After allowing the reaction solution to cool to 25 ° C., 80 mL of water was added and the mixture was stirred to extract the organic layer. The organic layer was washed successively with water and saturated brine, and dried to obtain the desired sensitizing dye as a black solid (0.53 g, 65% yield).

The obtained black solid was subjected to NMR analysis, and the following 30 hydrogen signals were detected and identified as a structure represented by the following formula (A-10) (carboxyl group hydrogen was not observed).

^{1 1} H-NMR (600 MHz, CDCl ₃ ): δ (ppm) = 5.96-6.06 (1H), 6.08-6.18 (1H), 6.85-6.95 (3H), 6 .94-7.04 (1H), 7.04-7.14 (4H), 7.15-7.25 (3H), 7.32-7.42 (2H), 7.46-7.56 (9H), 7.66-7.76 (1H), 7.78-7.88 (2H), 8.06-8.16 (1H), 8.57-8.67 (2H).

[Synthesis Example 3] Synthesis of sensitizing dye (A-51) 2.0 g of a bromo compound represented by the following formula (14) and 30 mL of dehydrated tetrahydrofuran were placed in a nitrogen-substituted reaction vessel and stirred at −72 ° C. Then, 3.0 mL of 1.6 M n-butyllithium hexane solution was added dropwise, and the reaction was carried out for 1 hour. After the reaction, 0.6 mL of dehydrated dimethylformaldehyde was added dropwise to the reaction solution, and the reaction was carried out for 2 hours. Then, the reaction solution was emptied into 150 mL of ice water, and the organic layer was extracted with methylene chloride. The organic layer was washed with water, separated, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by column chromatography (carrier: silica gel, solvent: hexane / toluene = 9/1 (volume ratio)) to obtain a yellowish white solid (0.99 g) of a formyl compound represented by the following formula (15). rice field.

In a nitrogen-substituted reaction vessel, 0.300 g of the formyl compound represented by the above formula (15), 0.150 g of the indenone compound represented by the above formula (12), and acetic acid / toluene = 5/2 (volume ratio) are mixed. 13.5 mL of the liquid was added, and the mixture was stirred at 90 ° C. for 4 hours. After allowing the reaction solution to cool to 25 ° C., 30 mL of toluene was added and the mixture was stirred to extract the organic layer. The cells were washed successively with water and saturated brine, and the obtained organic layer was dried to obtain the desired sensitizing dye as a dark brown solid (0.286 g, yield 74%).

The obtained black-brown solid was subjected to NMR analysis, and the following 30 hydrogen signals were detected and identified as a structure represented by the following formula (A-51) (carboxyl group hydrogen was not observed).

^{1 1} H-NMR (600 MHz, CDCl ₃ ): δ (ppm) = 1.87-1.90 (6H), 6.34-6.39 (2H), 7.33-7.36 (1H), 7 .39-7.42 (1H), 7.44-7.48 (3H), 7.54-7.60 (4H), 7.66-7.69 (2H), 7.82-7.86 (4H), 7.99-8.02 (3H), 8.03-8.08 (1H), 8.12-8.20 (1H), 8.30-8.40 (2H).

[Synthesis Example 4] Synthesis of sensitizing dye (A-60) 0.55 g of the bromo compound represented by the above formula (14) and 0.197 g of 5-formyl-2-thiopheneboronic acid in a nitrogen-substituted reaction vessel. , 20 mL of dimethyl sulfoxide and 0.124 g of potassium carbonate were added and stirred for 5 hours. After stirring, depressurization, deaeration and nitrogen substitution in the reaction vessel were repeated 5 times. Next, 0.012 g of palladium acetate and 0.038 g of butylbis (1-adamantyl) phosphine were added, and decompression, deaeration, and nitrogen substitution in the reaction vessel were repeated 5 times. Then, the mixture was stirred at 75 ° C. for 3 hours. After allowing the reaction solution to cool to 25 ° C., 150 mL of chloroform and 60 mL of water were added and stirred to extract the organic layer. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure to obtain a crude product. The crude product is purified by column chromatography (carrier: silica gel, eluent: hexane / toluene = 1/4 (volume ratio)), dried, and a yellow solid (0) of a formyl compound represented by the following formula (16). .543 g) was obtained.

In a nitrogen-substituted reaction vessel, 0.542 g of the formyl compound represented by the above formula (16), 0.256 g of the indenone compound represented by the formula (12), and acetic acid / toluene = 5/2 (volume ratio) mixed solution. 28 mL was added and stirred at 90 ° C. for 10 hours. After allowing the reaction solution to cool to 25 ° C., 50 mL of toluene was added and the mixture was stirred to extract the organic layer. The cells were washed successively with water and saturated brine, and the obtained organic layer was dried to obtain the desired sensitizing dye as a reddish brown solid (0.453 g, yield 67%).

The obtained reddish brown solid was subjected to NMR analysis, and the following 32 hydrogen signals were detected and identified as the structure represented by the formula (A-60) (hydrogen of the carboxyl group was not observed).

^{1 1} H-NMR (600 MHz, CDCl ₃ ): δ (ppm) = 1.82-1.86 (6H), 6.32-6.40 (2H), 7.30-7.35 (1H), 7 .35-7.40 (1H), 7.41-7.49 (3H), 7.53-7.59 (5H), 7.64-7.69 (2H), 7.80-7.88 (4H), 8.00-8.10 (5H), 8.27-8.34 (2H), 8.36-8.40 (1H).

[Synthesis Example 5] Synthesis of sensitizing dye (A-48) Synthesis Example 4 except that 4-formylphenylboronic acid was used instead of the raw material 5-formyl-2-thiophenboronic acid in Synthesis Example 4. The target sensitizing dye was obtained as a reddish brown solid (0.486 g, yield 75%).

The obtained reddish brown solid was subjected to NMR analysis, and the following 34 hydrogen signals were detected and identified as the structure represented by the formula (A-48) (hydrogen of the carboxyl group was not observed).

^{1 1} H-NMR (600 MHz, CDCl ₃ ): δ (ppm) = 1.83-1.87 (6H), 6.31-6.39 (2H), 7.28-7.34 (1H), 7 .33-7.39 (1H), 7.41-7.49 (3H), 7.53-7.60 (5H), 7.63-7.68 (2H), 7.81-7.88 (3H), 7.92-7.99 (3H), 8.01-8.08 (4H), 8.34-8.41 (1H), 8.41-8.45 (1H), 8. 63-8.69 (2H).

[Synthesis Example 6] Synthesis of sensitizing dye (A-61) 0.251 g of formyl compound represented by the following formula (17) and indenone compound 0 represented by the formula (12) in a nitrogen-substituted reaction vessel. A mixture of .124 g and acetic acid / toluene = 5/2 (volume ratio) was added, and the mixture was stirred at 90 ° C. for 6 hours. After allowing the reaction solution to cool to 25 ° C., 30 mL of toluene was added and the mixture was stirred to extract the organic layer. The cells were washed successively with water and saturated brine, and the obtained organic layer was dried to obtain the desired sensitizing dye as a reddish purple solid (0.268 g, yield 87%).

The obtained red-purple solid was subjected to NMR analysis, and the following 34 hydrogen signals were detected and identified as the structure represented by the formula (A-61) (hydrogen of the carboxyl group was not observed).

^{1 1} H-NMR (600 MHz, CDCl ₃ ): δ (ppm) = 1.50-1.54 (6H), 1.76-1.80 (6H), 6.31-6.40 (2H), 7 .31-7.36 (1H), 7.38-7.48 (6H), 7.62-7.67 (1H), 7.65-7.70 (2H), 7.71-7.76 (1H), 7.80-7.84 (1H), 7.87-7.92 (1H), 7.96-8.08 (2H), 8.12-8.23 (2H), 8. 28-8.37 (1H), 8.35-8.41 (1H), 9.22-9.28 (1H).

[Synthesis Example 7] Synthesis of sensitizing dye (A-62) Instead of the bromo form represented by the above formula (14) in Synthesis Example 4, the bromo form represented by the following formula (18) was used. Synthesis was carried out in the same manner as in Example 4 except that a formyl body represented by the following formula (19) was obtained.

The formyl compound represented by the above formula (19) is reacted with the indenone compound represented by the above formula (12) in a nitrogen-substituted reaction vessel in the same manner as in Synthesis Example 4, and the target sensitizing dye is purple. Obtained as a solid (0.37 g, 73% yield).

The obtained purple solid was subjected to NMR analysis, and the following 36 hydrogen signals were detected and identified as the structure represented by the formula (A-62) (hydrogen of the carboxyl group was not observed).

^{1 1} H-NMR (600 MHz, CDCl ₃ ): δ (ppm) = 1.50-1.54 (6H), 1.83-1.87 (6H), 6.32-6.38 (2H), 7 .28-7.34 (1H), 7.33-7.38 (1H), 7.38-7.47 (5H), 7.55-7.56 (1H), 7.61-7.71 (4H), 7.77-7.82 (1H), 7.83-7.87 (1H), 7.94-8.02 (3H), 8.03-8.07 (1H), 8. 16-8.21 (1H), 8.25-8.32 (2H), 8.33-8.40 (1H).

[Example 1]
Titanium oxide paste (PST-18NR manufactured by JGC Catalysts and Chemicals Co., Ltd.) was applied by the squeegee method on a glass substrate coated with a fluorine-doped tin oxide thin film. After drying at 110 ° C. for 1 hour, it was calcined at 450 ° C. for 30 minutes to obtain a titanium oxide thin film having a film thickness of 6 μm. Next, the sensitizing dye (A-4) obtained in Synthesis Example 1 was dissolved in an acetonitrile / t-butyl alcohol = 1/1 (volume ratio) mixture to prepare 50 mL of a solution having a concentration of 100 μM. A glass substrate coated with titanium oxide and sintered in a solution was immersed at 25 ± 2 ° C. for 15 hours to adsorb the dye to obtain a photoelectrode.

A platinum thin film having a thickness of 15 nm was formed by a sputtering method using an auto fine coater (JFC-1600 manufactured by JEOL Ltd.) on a glass substrate coated with a fluorine-doped tin oxide thin film, and used as a counter electrode.

Next, a spacer (heat fusion film) having a thickness of 60 μm is sandwiched between the optical electrode and the counter electrode and bonded by heat fusion, and the electrolytic solution (0.1 M lithium iodide, 0.6 M iodine) is attached through the holes of the counter electrode. After injecting dimethylpropyl imidazolium oxide, 0.05 M iodine, 0.5 M 4-t-butyl pyridine) / 3-methoxypropionitrile solution), the pores were sealed to prepare a photoelectric conversion element.

Light generated by a pseudo-sunlight irradiation device (OTENTO-SUN III type manufactured by Spectrometer Co., Ltd.) is irradiated from the optical electrode side of the photoelectric conversion element, and a source meter (Model 2400 General-Purpose Source Meter manufactured by KEITHLEY) is used. The current-voltage characteristics were measured using. The light intensity was adjusted to 100 mW / cm ² . Table 1 shows the obtained measurement results and the initial photoelectric conversion efficiency. Table 1 also shows the results of photoelectric conversion efficiency measured in the same manner for the characteristic change after irradiation with light for 20 hours.

[Examples 2 to 11]
Current-voltage characteristics, initial and initial and photoelectric conversion elements of the photoelectric conversion element manufactured in the same manner as in Example 1 except that the sensitizing dyes shown in Table 1 were used instead of (A-4) as the sensitizing dye for photoelectric conversion. Table 1 summarizes the photoelectric conversion efficiency after 20 hours of light irradiation.

[Comparative Example 1 to Comparative Example 5]
As the sensitizing dye for photoelectric conversion, the same as in Example 1 except that the sensitizing dyes shown in the following (B-1) to (B-5), which do not belong to the present invention, are used instead of (A-4). Table 1 shows the current-voltage characteristics and the photoelectric conversion efficiencies of the manufactured photoelectric conversion element after initial and 20-hour light irradiation.

From the results in Table 1, by using the sensitizing dye composition for photoelectric conversion containing the sensitizing dye of the present invention, the photoelectric conversion efficiency is high and the high photoelectric conversion efficiency is maintained even if the light irradiation is continued for a long time. It was found that a photoelectric conversion element can be obtained. On the other hand, the photoelectric conversion efficiency of the photoelectric conversion element using the photoelectric conversion sensitizing dye of the comparative example was insufficient.

The sensitizing dye composition for photoelectric conversion comprising the sensitizing dye of the present invention is useful for a highly efficient and highly durable photoelectric conversion element and a dye sensitized solar cell, and can efficiently convert solar energy into electric energy. As a solar cell, it can provide clean energy.

1 Conductive support 2 Dye-supported semiconductor layer 3 Electrolyte layer 4 Counter electrode 5 Conductive support

Claims (6)

A sensitizing dye represented by the following general formula (1).

[In the formula, Ar represents an aryl group having 6 to 36 carbon atoms which may have a substituent.
R ¹ to R ⁴ may be the same or different, and hydrogen atom, halogen atom, cyano group, hydroxyl group, nitro group, nitroso group, thiol group,
A linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent,
A cycloalkyl group having 3 to 36 carbon atoms which may have a substituent,
A linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent,
A cycloalkoxy group having 3 to 36 carbon atoms which may have a substituent,
A linear or branched alkenyl group having 2 to 36 carbon atoms which may have a substituent,
Aryl groups having 6 to 36 carbon atoms, which may have substituents,
Alternatively, it represents an amino group having 0 to 36 carbon atoms which may have a substituent.
R ¹ to R ⁴ may be bonded to each other by adjacent groups to form a ring.
X represents a sulfur atom, an oxygen atom or CR ⁵ R ⁶ .
R ⁵ and R ⁶ may be the same or different, and may have a substituent. They may have a linear or branched alkyl group having 1 to 36 carbon atoms, or a substituent. Represents an aryl group having 6 to 36 carbon atoms.
Ar, "aryl group having 6 to 36 carbon atoms" represented by R ¹ to R ⁶ , and "cycloalkyl group having 3 to 36 carbon atoms" represented by R ¹ to R ⁴ , "carbon" When the "linear or branched alkoxy group having 1 to 36 atoms", "cycloalkoxy group having 3 to 36 carbon atoms" and "amino group having 0 to 36 carbon atoms" have a substituent, the substitution thereof. The group is a halogen atom; a cyano group; a hydroxyl group; a nitro group; a nitroso group; a thiol group; a linear alkyl group having 1 to 30 carbon atoms; a branched alkyl group having 3 to 30 carbon atoms; 3 to 30 cycloalkyl groups; linear alkoxy group with 1 to 30 carbon atoms; branched alkoxy group with 3 to 30 carbon atoms; cycloalkoxy group with 3 to 30 carbon atoms; 2 carbon atoms A group consisting of a linear or branched alkenyl group of ~ 30; an aryl group having 6 to 30 carbon atoms; an unsubstituted amino group; an amino group having a substituent of 1 to 16 carbon atoms; and a carboxylic acid ester group. It is one or a plurality of groups selected from the above, and when a plurality of groups are contained, they may be the same or different from each other.
A "linear or branched alkyl group having 1 to 36 carbon atoms" represented by R ¹ to R ⁶ and a "linear or branched alkyl group having 2 to 36 carbon atoms" represented by R ¹ to R ⁴ . When the "branched alkenyl group" has a substituent, the substituent is a halogen atom; a cyano group; a hydroxyl group; a nitro group; a nitroso group; a thiol group; a cycloalkyl group having 3 to 34 carbon atoms; and 1 carbon atom number. Linear alkoxy groups of ~ 34; branched alkoxy groups of 3 to 34 carbon atoms; cycloalkoxy groups of 3 to 34 carbon atoms; aryl groups of 6 to 34 carbon atoms; unsubstituted amino groups; carbon It is one or more groups selected from the group consisting of an amino group having a substituent having 1 to 16 atoms; a carboxyl group; and a carboxylic acid ester group, and when a plurality of groups are contained, they may be the same or different from each other. good.
Z represents a monovalent group represented by the following general formula (2) . ]

[In the formula, R ⁷ to R ¹² may be the same or different, hydrogen atom,
A linear or branched alkyl group having 1 to 18 carbon atoms which may have a substituent,
A linear or branched alkoxy group having 1 to 18 carbon atoms which may have a substituent,
Alternatively, it represents a linear or branched alkenyl group having 2 to 18 carbon atoms which may have a substituent.
R ⁷ and R ⁸ , R ⁹ and R ¹⁰ , and R ¹¹ and R ¹² may be connected to each other to form a ring.
m represents an integer of 0 to 2, n represents an integer of 0 to 4, and when m is 2 or n is an integer of 2 to 4, a plurality of R ⁷ to R ¹² existing are the R ⁷ thereof. They may be the same or different from each other, R ⁸ to each other, R ⁹ to each other, R ¹⁰ to each other, R ¹¹ to each other, and R ¹² to each other.
"Linear or branched alkyl group having 1 to 18 carbon atoms" represented by R ⁷ to R ¹² , "linear or branched alkoxy group having 1 to 18 carbon atoms", and "carbon". When the "linear or branched alkenyl group having 2 to 18 atoms" has a substituent, the substituent has a halogen atom; a cyano group; a hydroxyl group; a nitro group; a nitroso group; a thiol group; and 3 to 3 carbon atoms. 16 cycloalkyl groups; linear alkoxy groups with 1 to 16 carbon atoms; branched alkoxy groups with 3 to 16 carbon atoms; cycloalkoxy groups with 3 to 16 carbon atoms; 6 to 34 carbon atoms One or more groups selected from the group consisting of an aryl group; an unsubstituted amino group; an amino group having a substituent having 1 to 16 carbon atoms; a carboxyl group; and a carboxylic acid ester group, and a plurality of groups thereof. If they are, they may be the same or different from each other.
R ¹³ and R ¹⁴ represent an acidic group selected from the group consisting of a hydrogen atom or a carboxyl group, a sulfonic acid group, a phosphoric acid group, a hydroxamic acid group, a phosphonic acid group, a boric acid group, a phosphinic acid group, and a silanol group. , At least one of R ¹³ or R ¹⁴ shall be an acidic group. ] In the general formula (2), R ⁷ ~ R ¹² The sensitizing dye according to claim 1, wherein is a hydrogen atom or an unsubstituted linear or branched alkyl group having 1 to 6 carbon atoms. The sensitizing dye according to claim 1 or 2, wherein m is 0 and n is 0 in the general formula (2). A sensitizing dye composition for photoelectric conversion containing the sensitizing dye according to any one of claims 1 to 3. A photoelectric conversion element using the photoelectric conversion sensitizing dye composition according to claim 4. A dye-sensitized solar cell using the photoelectric conversion element according to claim 5.

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